# Assessing Photoreceptor Structure and Function in Normal and Diseased Retinae

> **NIH NIH R01** · MEDICAL COLLEGE OF WISCONSIN · 2020 · $486,444

## Abstract

ABSTRACT .
Inherited retinal degenerations affect approximately 1 in 1,500 individuals in the US, and given the
extreme genotypic and phenotypic heterogeneity, the prospect of treating these devastating diseases is a
formidable task. Nevertheless, trials examining novel therapeutic strategies are underway. An important
key to success in the early phases of such trials is selection of patients with reasonable therapeutic
potential – for example, a retina with no remaining cone photoreceptors would not be the best target for a
gene therapy approach aiming to restore cone function. In addition, current clinical tools for assessing
retinal structure are relatively insensitive and macroscopic, limiting the ability to monitor therapeutic
response in these patients. As such, there is a need for sensitive, noninvasive, high-resolution
techniques to assess photoreceptor structure. The Advanced Ocular Imaging Program has made
significant advances on this front – advancing innovative adaptive-optics (AO) imaging instrumentation for
probing photoreceptor inner- and outer-segment structure with single-cell resolution, creating software for
extracting quantitative metrics of the photoreceptor mosaic, and developing tools for making accurate and
reliable measurements of photoreceptor structure from optical coherence tomography (OCT) images of
the retina. From a clinical perspective, these tools are in relative infancy, thus we propose to help
accelerate their translation through the following specific aims: 1) Define the variability in the remnant
cone population in human patients with achromatopsia (ACHM), 2) Characterize the integrity of the
photoreceptor mosaic in individuals with L/M opsin mutations, and 3) Elucidate the rod/cone contribution
to the photoreceptor layers in OCT images. The specific diseases being studied have a wide range of
rod/cone involvement, are current or emerging targets for treatment efforts, and continue to represent a
major strength of our multidisciplinary research team. This work is expected to have a significant positive
impact, with the high-resolution genotype-phenotype relationships identified here providing a better
understanding of the therapeutic potential in patients with inherited retinal degenerations as well as
producing validated tools for assessing photoreceptor structure in emerging clinical trials. Our proposal
addresses two emerging needs identified in the NEI Publication “Vision Research: Needs, Gaps, and
Opportunities”: “Characterize the macula and perifoveal regions of the retina to better understand the
predilection of the macula for disease,” and “Translate high-resolution retinal imaging technologies, like
adaptive optics, into cost-effective and easy-to-use platforms for routine clinical use.”

## Key facts

- **NIH application ID:** 9994928
- **Project number:** 5R01EY017607-13
- **Recipient organization:** MEDICAL COLLEGE OF WISCONSIN
- **Principal Investigator:** Joseph Carroll
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $486,444
- **Award type:** 5
- **Project period:** 2008-08-15 → 2022-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9994928

## Citation

> US National Institutes of Health, RePORTER application 9994928, Assessing Photoreceptor Structure and Function in Normal and Diseased Retinae (5R01EY017607-13). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/9994928. Licensed CC0.

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